IO wrapper to log all data passing through to a file

io_logger.cr

class IOLogger < IO
  @@log_index = 0

  def initialize(@io : IO)
    @@log_index += 1
    @log = File.new("log#{@@log_index}.txt", "w")
    @mode = :waiting
  end

  def read(slice : Bytes)
    bytes = @io.read(slice)
    if bytes > 0
      if @mode != :reading
        @mode = :reading
        @log.puts
        @log.puts "<<<<"
      end
      @log.write slice[0, bytes]
      @log.flush
    end
    bytes
  end

  def write(slice : Bytes)
    if @mode != :writing
      @mode = :writing
      @log.puts
      @log.puts ">>>>"
    end
    @log.write slice
    @log.flush
    @io.write(slice)
  end

  def close
    @io.close
  end

  def flush
    @io.flush
  end
end